Most electronic cameras that are currently on the market include an autofocus mechanism in order to produce sharp images over a range of object distances. Typically, an electronic controller receives an indication from a sensor (which may be the image sensor of the camera itself or an external sensor) of the necessary focus adjustment, and drives a electromechanical element to adjust the focal distance of the camera optics accordingly. Even the tiny camera modules that are integrated in smartphones have autofocus capability, typically using a voice-coil motor (VCM) to adjust the distance between the camera lens and the image sensor.
U.S. Patent Application Publication 2010/0321506 describes a set of calibration procedures that can be run to assist in calibrating a camera module, such as may be intended for installation into a mobile consumer device. The procedures include lens shading calibration, white balance calibration, light source color temperature calibration, auto focus macro calibration, static defect pixel calibration, and mechanical shutter delay calibration. Each of these procedures may generate data that can be potentially be stored in non-volatile memory on board the camera module for use during operation.